The invention relates to a compound or salts thereof suitable for use as a binder for mineral fibres, i.e. man made vitreous fibres (MMVF), for example glass slag or stone wool, i.e mineral wool, in particular stone wool, a binder composition comprising such a compound, a process for providing said compound and composition, a mineral fibre product provided with such a binder and the use of said compound and composition as a mineral fibre binder.
Phenol and formaldehyde resins which are mainly used as binders for glass or stone wool are toxic.
During application and curing of the benders, after provision thereof to the mineral fibres, phenol, formaldehyde and ammonia are released. From an environmental point of view this is undesirable.
Furthermore during application, mostly by spraying, of the binder onto the spun glass or stone fibres a large amount of binder is lost, which is almost impossible to recover for re-use.
According to a first aspect of the present invention there is provided a compound according to the claims 1-12.
The inventors have found that such a compound is particularly suitable for use as a binder for mineral wool products, whereby since the compound is preferably non-polymeric and has a low molecular weight, costs are minimized with respect to polymeric binders, and the handling of such non-polymeric compounds is straightforward.
Since the compound is soluble in water no further solublizing agents are required in order to provide a soluble binder having a desired viscocity for adhering to the mineral fibres.
Moreover on applying or curing the compound according to the present invention, no toxic materials are released into the environment.
The compounds according to the present invention also have desirable properties with respect to hardness, scratch resistance, chemical resistance, mechanical properties and adhesive properties once cured.
In formula (I) the R-groups, with the exception of R9 can form either together or with the adjacent carbon atoms, or with the carbon atoms on B or Y a cyclo aliphatic group.
Preferably, B is a 1,2-ethylene, 1,2-ethylidene, 1,3-propylene, 1,2-cyclohexyl, 1,2-phenylene, 4-carboxyl-1,2-phenylene, 1,3-phenylene, 1,4-phenylene and/or 1,2 cyclohex-4-enyl radical.
B can be saturated or unsaturated.
B can be substituted with for instance a (C1-C12) alkyl group which is saturated or unsaturated.
B can form a part of a polymer. Such polymers can be obtained by the reaction of anhydride function polymers with a xcex2-hydroxy alkylamine or a derivative thereof.
Anhydride functional polymers can for instance be obtained by a radical polymerisation of Maleic anhydride with styrene and with (meth)acrylate monomers.
Maleic anhydride can also be grafted onto unsaturated compounds. A reaction between maleic anhydride and oils, such as for instance linseed oil, results in products, which are called maleinised oils, which may be grafted onto unsaturated compounds, used as a comonomer or mixed into the compounds.
If B does not form part of a polymer, the molecular weight of the compounds, is less than 1000 and preferably less than 600.
According to a second aspect of the present invention, there is provided a curable composition suitable for use as a binder for mineral fibers, according to claims 13-17.
Such a composition exhibits the properties as described above for the compound.
The composition may contain more than 10 wt %, for example more than 25 wt %, and preferably 50 wt % or more of the compound according to claims 1-12.
Standard binding additives can improve the binder, examples of such additives include: aminotropyl siloxane to improve the adhesion on glass, stabilizers to prevent thermal or UV degradation and surface-active compounds. Fillers, such as clay, silicates, magnesium sulfate and pigments, such as titanium oxide, can also be applied, as well as hydrophobising agents such as fluorine compounds, oils, minerals and silicone oil (reactive or ion reactive).
The composition may also be applied in combination with other binder compositions such as for instance phenol-formaldehyde resins.
A very good binding strength is achieved when an accelerator is added to the composition, a preferred accelerator being sodium hypophosphite.
Furthermore since the binder composition is preferably composed of low molecular weight compounds, it has a viscosity at high concentrations which is lower than polyacrylic binders for example.
This is advantageous since on curing, following an initial flash evaporation, any water present usually evaporates. Before curing the composition still has a viscosity which allows it to be sprayed onto the mineral fibres and adhere thereto once sprayed.
Since the composition is intrinsically water soluble, no solublizing agents need to be provided thereto in order to enable application of the composition to the mineral fibers, the viscosity of the composition being high enough to adhere well to the mineral fibers and low enough, as stated above to enable sprayability. A decrease in the viscosity can be achieved by heating the composition to a temperature below which an eventual condensation reaction takes place.
According to a third aspect of the present invention there is provided a compound according to claim 18.
According to a fourth aspect of the present invention there is provided a process for providing a compound suitable for use as a binder for mineral fibers according to the claims 19-28, see FIG. 7.
For a schematic illustration of the reaction, for example, between tetrahydro pthalic anhydride and diethanolamine see FIG. 1.
The reaction between the anhydride and the alkanolamine can proceed without a solvent, in water or in an organic solvent. Preferably, the reaction starts in the presence of  less than 40 weight % of water compared to the reactants.
The distillation of the water can, if desired, proceed at 1 bar, under vacuum or azeotropically.
The equivalent ratio anhydride: alkanolamine lies generally between 1, 8:1, 0 and 1, 0:1, 8. Preferably, this ratio lies between 1, 5:1, 0 and 1:1, 5.
In case a high crosslink density is desired, di- or trialkanolamines or carboxylic acid functional anhydrides can be applied as starting materials.
Another aspect of the present invention relates to the compound obtainable via this process.
The reaction of diethanolamine with an activated ester, such as a cyclic anhydride, can also result in an ester amine.
However, the same product can also be formed out of the xcex2-hydroxyalkylamide because of an internal rearrangement. The inventors have measured that the xcex2-hydroxyalkylamide and the ester-amine form an equilibrium with each other usually in a 85/15 ratio. In case the ester-amine reacts further with a cyclic anhydride another xcex2-hydroxyalkylamide is formed, see FIG. 2, for example.
The applied compound can also be obtained by the reaction between an alkanolamine, such as for instance described above and a compound having one carboxylic acid group and a activated carboxylic acid group.
The compound having a carboxylic acid group and an activated carboxylic acid group is preferably a compound according to the following formula: 
In which
B has the meaning as referred to in claims 5 and 7.
L=
In which R7 is a (C1-C12) branched or linear alkyl group.
Examples of appropriate compounds with one carboxylic acid group and one activated carboxylic acid groups are alkyl esters, such as for instance mono (m) ethyladipate and mono (m) ethylsebacate. Activated carboxylic acid groups are for instance anhydrides and thioesters.
The compound applied in the invention can also be obtained by reaction between a cyclic anhydride, such as described above, and an alcohol after which the obtained reaction product in situ reacts with an alkanolamine.
Examples of appropriate alcohols are (C1-C10) alcohols. Preferably methanol or ethanol are applied.
Another binder composition according to the invention can be obtained by reacting linear polyanhydrides with alkanolamines or derivatives.
It is also possible that the carboxylic acid groups and the xcex2-hydroxy alkylamide groups are not located on the same compound.
According to a further aspect of the present invention, there is provided a composition suitable for use as a binder, said composition containing one or more compounds with carboxylic acid groups or xcex2-hydroxyalkylamide groups. Suitable water soluble molecules having xcex2-hydroxyalkylamides can be obtained as shown in FIGS. 4 and 5 wherein the starting materials are dimethyl adipate and caprolactone respectively. Because no salt formation is possible with these molecules, it is known that predominantly ( greater than 70%) the amides are formed.
This reaction can proceed in the presence of a catalyst such as for instance sodium methanolate. If no catalyst is used, the reaction should be performed at a higher temperature.
The carboxylic acid containing compounds are fully or partially water soluble compounds, such as maleic acid, glutaric acid, adipic acid, 2-methyl adipic, succinic acid, citric acid and tartaric acid.
The carboxylic acid groups containing compounds can also be obtained by partial or full reaction of high functional alcohols, mono di and polysaccharides, such as sucrose or polyvinylalcohol, with cyclic anhydrides as described above.
Water soluble compounds are compounds which can be homogeneously divided in water. Eventually, emulsions or dispersions can be applied.
To further improve the water solubility of the carboxylic acid functional compounds, a base can be added, for example, a base is added which evaporates during the curing reaction. Examples of such bases are amines such as ammonia, methylamine, diethylamine and triethylamine.
In another preferred form of the invention addition products having xcex2-hydroxyalkylamides with cyclic anhydrides are used. FIG. 6 shows one of the resultant reaction products.
According to another aspect of the present invention there is provided a cureable binder according to claims 30-33.
According to another aspect of the present invention there is provided a process for providing a bound mineral fibre product according to claims 34 and 35. The binder composition is preferably sprayed onto the fibres just after the spinning of the glass or the stonemelt. The curing of the binder composition proceeds by bringing the sprayed fibres into an oven. The curing time is mainly dependent on the components used in the binder and on the desired oven temperature. xcex2-hydroxy alkylamide groups attached to an aromatic group, for instance, will react slower with carboxylic acids than the ones attached on an aliphatic group and aromatic carboxylic acids will react faster with xcex2-hydroxy alkylamides than aliphatic carboxylic acid groups. The curing temperatures lie mostly between 150xc2x0 C. and 400xc2x0 C. and preferably between 200xc2x0 C. and 400xc2x0 C. The curing times lie mostly between 10 sec and 600 sec.
Unused binder, can, due to its low reactivity, be recycled. If water of the binder composition is evaporated during this process, water may be returned to the process to return the viscosity to the desired level, if needed.
When spraying binder composition to the fibers does not end in the wool but is collected in process water either directly or when clearing walls and ducts in the spinning chamber system. This water may be used as dilution water for the binder, where by loss of binder is avoided/reduced.
The raw materials for fibres composition can be converted to a melt in the conventional manner, for instance in a gas heated furnace or in an electric furnace or in a shaft or cupola furnace. The melt can be converted to fibres in the conventional manner, for instance by a spinning cup process or by cascade rotor process, for instance described in WO 92/06047.
Man made vitreous fibres (MMVF) are made from vitreous melt, such as of stone, slag, glass or other melts. The melt is formed by melting in a furnace a mineral composition having the desired analysis. This composition is generally formed by blending rocks or mineral to give the desired analysis. The binder can be used on MMVF which are durable in use but which have been shown to be biologically soluble e.g. as described in EP 791 087 and EP 596 088.
The fibres can have any convenient fibre diameter and length. Generally the average fibre diameter is below 10 xcexcm e.g. 5 xcexcm. Usually a mineral wool product contains 1-15 wt. % binder, preferably 2-10 wt. %. Usually the binder is added to the fibres just after fibersation of the melt. Generally the mineral wool product is in form of a slab, sheet or other shaped articles. Products according to the invention may be formulated for any of the convential purposes of MMV fibres, for instance slabs, sheets, pipes or other shaped products that are to serve as thermal insulation, fire insulation and protection or noise reduction and regulation or as horticultural growing media. The binder can also be used to coat the surface of either the fibres or one or more of the surfaces of the mineral wool product. Silane and mineral oil are typical additives for mineral wool products. A typical phenolic binder is described in U.S. Pat. No. 4,710,406.
According to yet another aspect of the present invention there is provided the use of the compounds and/or compositions of the present-invention as binding agents for mineral fibre products.